A region of space contains an electric field E = E1i + E2j where E1 and E2 are positive constants. A square frame has corners located at (x1, y1, z1) = (-a, 0, -a), (x2, y2, z2) = (-a, 0, +a), (x3, y3, z3) = (+a, 0, -a) and (x4, y4, z4) = (+a, 0, +a). What is the magnitude of the electric flux through the frame?